Very close to J3 connecting to the monarch flight slots manchester front panel.
Then press CMD to enter the edit mode. .
The Scoutmaster is 1024 weeks slow,.e.Trimble PathfinderBasic with very leaky battery Black color battery marked: L-104 FCE 04 95 The bottom view of the back of the analog OCB shows an added diode and added resistor.Trimble (HP May 1969, 702/69 ; 455/63.1; 702/195; 708/ extended bandwith signal-TO-noise ratio enhancement methods AND means, Charles.U17 U18: TNL 17606 uubi9249 U15, U16 U20 same as in the Transpak The battery is marked: Z/05/91 Lithium Battery.6 Volts Size AA warning: Fire, Explosion or Severe Burns May Result if Mistreated. .But has the GPS week rollover error so the date is wrong. .VR1 may be the display contrast pot.
U5 - HD44780 - the standard alphanumeric LCD controller chip U6 - LM2904M -low power dual op amp - Probably related to the display temperature measurement that different from the internal temperature measurement.
Texas Manufacturing Facility, when the Trimpack II arrived the POS display showed: 30:23:15.5 N 97:42:45.9W 918 feet.There are two (u17 U18) Trimble custom DSP chips installed. .Sometimes compact florescent lights or dimmer switches generate interference.Parts U1 - MC68HC000FN10 32 bit CPU the 10 suffix may mean a 10 MHz clock rate U5 U9 - HM62256LFP-10 Hitachi 32 k x 8 bit Static RAM chips, the -10 may mean 100 ns access time U2, U3, U4, U6,.I was part of a small group acquired from Tracor who had the certification expertise and who set up the operation there in Austin.The internal construction is considerably different from the civilian units. .The board does have a smps power supply and the TTL - RS-232 interface including line conditioning for 4 I/O lines.